C. B. LOWE
LIBRARY & LEARNING RESOURCES SERVICE
This book must be returned on or before the date last stamped
PLEASE RETURN TO CAMPUS INDICATED
Lancaster Annexe Tel. 88121
Poulton Campus Tel. 884651
Preston Campus Tel. 58692
C. B. LOWE
A HEYWOOD BOOK
TEMPLE PRESS BOOKS LTD
C. B. LOWE 1963
Filmset and reproduced by Photoprint Plates Ltd., Basildon, Essex
Printed in England by Perivan (Litho) Ltd., Southend-on-Sea
Whilst it has become increasingly recognized that Isometric views
are almost essential for explanatory hand-books of various mechanisms,
sometimes by way of ghost drawings, and in other cases by exploded
views showing the component parts, it does not seem to have been
generally recognized that the advantages and clarity of this form of
portrayal can be applied in an equal degree to actual working drawings.
One of the reasons may be that heretofore there has not been
available a simple work to form a basis for instruction in its practical
application. I consider that Isometric and Trimetric Drawing does meet
In my experience on automobile and aircraft armament design and
construction, too few of the draughtsmen I have known have been
able to make pictorial engineering drawings, due either to their
non-appreciation of its benefits, or their lack of the constant practice
by which it becomes a quick and easy medium of expression.
Those who use it freely have, in my opinion, a much more facile
designing ability than those unversed in its art.
This book is written in simple language and includes small but
important points which, though valuable, I have not previously seen
Mr C. B. Lowe has long been an advocate of pictorial engineering
drawing and I am very glad to see that in this hand-book he has put
his wide knowledge of the subject within reach of our coming
draughtsmen and designers.
2- 1 0-62
Orthographic, or flat, drawing employing three or more views will
always be the main method used when recording or setting out
dimensioned shapes. These are drawn using either first or third
angle projection. There are many occasions, however, when the
addition of a three-dimensional view would be most helpful in order
to clarify some particularly obscure feature.
Sometimes even engineers with long experience are puzzled
when studying ordinary flat drawings of complicated parts, which
although correctly drawn, may have some detail which is not im-
mediately understood. It is in such cases that the inclusion of additional
pictorial views has great value, permitting instant recognition of
complicated shapes and detail which might otherwise be obscure.
Pictorial drawing may be carried out in three main ways:
Isometric, The simplest form.
Trimetric, More difficult but sometimes necessary.
Perspective, Essential for artistic representation.
Of these, isometric is the most favoured because of its relative
simplicity. This is brought about by the fact that its three planes are
equally tilted to the eye of the beholder and so have equality of
measure along the edge lines. It must be admitted, however, that this
equal tilting can bring disadvantages in some rare cases; for instance
certain simple forms can appear to turn themselves inside-out, but
this is an optical illusion which ceases as the drawing grows with
The only other slight disadvantage which might occur is the
coincidence of some lines being in the direct sight path of others.
When this is likely to occur, the draughtsman would be wise to use a
trimetric attitude with the most direct plane (the fullest plane)
showing the feature or features which require particular emphasis.
Both isometric and trimetric drawing are geometrically pure
forms of drawing, being projections from orthographic views. There
is no need for guesswork. Perspective vanishing does not occur in
isometric or trimetric drawing; both, however, may be regarded as
perspective at an infinite distance. To some extent the lack of vanish-
ing is evident; it depends very much on the aspect ratio of the subject
depicted. In compact subjects it is barely noticeable, particularly if
they contain a lot of detail.
In any case we must keep in mind the fact that we are not trying
to produce an artistic creation but a clear and easily understood
mechanical document which is obvious in its meaning to all who study
All draughtsmen should be able to draw in isometric and in
trimetric. They are not difficult once the main rules are mastered.
Perspective drawing, a most absorbing subject, is not taught in
this book. It requires constant practice and is generally left to spe-
HAVING EQUALITY OF MEASURE— ISOS equal. METRON measure
Isometric Projection is a method of drawing solid objects using the
same scale of linear measurement on each of the three planes.
This is done by picturing the object cornerwise and at such a
downward angle that each plane is equally inclined to the view, as
in the figure below.
Because each plane is equally inclined, all edges are proportion-
ately reduced in apparent length, being foreshortened to a known
ratio. It is necessary therefore to use a smaller scale when producing
The reason for this reduced scale, and how it is determined,
must be clearly understood by the draughtsman if he is to be con-
fident of every line of his drawing.
To this end, a simple exercise is given in the diagrams overleaf.
Using everyday articles as models such as a matchbox and a cube of
sugar, arrange them so that when viewed from above they appear
as set out in the top figure overleaf.
Standing square to the desk or
board on which they are placed, look
downward and you see the plan view,
Figure I .
Moving backwards in a straight
line, but still keeping square to the
desk, you will see an ever-changing
aspect, and the front corner angles
of the box and cube will appear
gradually to change from 90° to some
increased angle according to the angle
of view, as in Figures 2 and 3.
If your angle of view alters so
much that your sight line is 90° from
its original position then natucally
the angles will have opened out so
that they now form a straight hori-
zontal line, the whole forming a cor-
ner elevation, Figure 4.
The isometric view lies between
the two extremes and it will be
noted how the dotted lines repre-
senting the invisible edges of the
cube meet at the same point as the
top front corner of the cube. Thus
the nine lines forming the visible
edges are all of the same length.
Only in an isometric cube does this
By comparing the length of the
box taken from the plan with the
lengths in other views, you will see
the variation in amounts of fore-
Edge of desk
^Ue OiXHtoet/iic Scale
Having seen the necessity of a reduced scale, we now learn how it is
determined. It is a precise measurement for a given degree of fore-
shortening and its ratio to flat measure should be fully understood.
If we draw an inch cube isometrically but neglect to use the
isometric scale it will look like Figure 5, i.e. too large.
Compare the incorrectly scaled
cube above with the cube drawn
to correct scale, right. (Figure 6.)
It will be seen, therefore,
that the reason for using a speci-
ally reduced scale is because we
are drawing lengths which are
at an angle to our vision.
with ordinary inch
There are certain parts of isometric or trimetric which retain
ordinary scale. A sphere for example can only appear at its true
diameter no matter from what angle it is being regarded. It can never
be anything other than its true diameter. For the same reason a
circular shaft or cylinder always shows its full diameter, as do circular
holes, their full diameter being expressed as the major axis of an ellipse.
In Figure7a l^-in. cube
is shown with a circular
feature on each of its planes.
Note that all repre-
sentations of diameter, ex-
pressed by ellipses, have
full scale on their major axes.
Two Methods of making an Isometric Scale:
I* dia. X I* lonq
RIGHT HAND PLANE
/& dia. cylinder
LEFT HAND PLANE
Scale need, not start
at intersection of angles
There may be a little confusion in connection with the isometric
sight angle, which may be taken as 35°, and the 30° angle at which
normal isometric lines are drawn.
Referring back to the cube of sugar in Figure 2 you will remember
that at the isometric angle of view, the top front corner of the cube
(solid lines) meets the bottom rear corner (dotted lines). Thus, nine
solid lines depict the visible cube edges and three dotted lines indicate
the hidden edges. These twelve lines are all of the same length, in fact
the isometric cube is constructed from six equilateral triangles fitting
together to form a hexagon, with two of its sides vertical, for the
outside shape. From this you will see how the 30° angle comes to be
used for normal isometric lines. It will also correct the mistaken
belief held by some, that the 30° angle has been chosen as convenient
because set squares are made to that angle.
The 30° angle at which isometric lines are drawn, must not be
confused with the sight angle
(the angle at which you are
looking downwards). The sight
angle, which from now on will
be shown by the symbol > is
decided by the fact that we are
looking down on the cube placed
cornerwise so that our sight line
passes through its furthermost
corners. How we arrive at this is
shown in Figure 10.
When a circle is tilted to the eye it becomes an ellipse.
Ellipses around a given axial centre line all have the same major/minor
proportion. This applies to isometric ellipses or others.
A small nick in pencil lead
prevents overriding thread
Figure I 2
Hold ends of thread
firmly with finger
The ellipse is the most beautiful of all geometric shapes and the care
taken in drawing it is amply repaid. Approximate curves made by a
combination of radii should be avoided as they are usually distorted
and most displeasing. A freehand ellipse is better than one made by
radii. Correct major to minor proportions are necessary and in the
case of isometric ellipses are easily decided, as shown in Figure 1 1.
The most practical way of striking elliptical curves is by using
cotton or nylon thread as shown in Figure 12 (opposite). The radius of
the arc for obtaining the focal points is equal to half the major axis
for an ellipse of any size or proportion.
Elliptical masks are a boon to the draughtsman enabling him to
draw ellipses crisply and quickly, but if these aids are not available
ready-made, they can be made from thin cardboard or stiff paper.
When making them, it is helpful to add two cross lines at 30° to the
major axis in addition to the major and minor axis lines for they
indicate at which point to stop the pencil when drawing arcs such as
those for the corner radii in Figure 12 (below).
formed by radii
Before starting a three-dimensional drawing, be it isometric or tri-
metric, it is necessary to have before you an orthographic drawing of
the subject to be illustrated.
When setting out angles on any of the three planes it is not pos-
sible to use an ordinary protractor because the angles need to be
converted; angles, like lengths, become foreshortened. Each angular
line on any plane must therefore be subject to the scale of lengths used
on that particular plane.
To determine an angle, we know that a line rises so much in a
distance of so much. In flat drawing these distances or lengths are at
right angles to each other. They are not so in three-dimensional
drawing, as can be seen below, Figure 13 (right).
sc a le
It is helpful to have the symbol cube before you, for it avoids
confusion and shows from which datum the angle is to be measured.
When setting out angles on trimetric planes, H and L are converted to
the scale used for the particular direction concerned.
The ellipse of correct proportion and at its correct orientation for
its given plane provides an 'on the spot' means of measurement
for foreshortened lengths in any direction on that plane if the measure-
ments are made on lines from the ellipse centre or parallel with
them. (Figure 14.) This rule applies to all planes, isometric or other-
wise. It is essential to use an ellipse of
the correct proportion for the plane
From these varying lengths it is
now a simple matter to find the pro-
portions of ellipses which represent
circles around the radial lines, which
now become axial centre lines.
A study of the drawing on page 19 will show you the following facts:
All cylinders can be measured across their parallel lines.
All major axes are at right angles to the cylinder centre lines.
Scales used for radial lengths vary with their angular attitude.
The proportions of cylinder lengths to minor axes are in inverse
Fiqure I 4
The length of any
line across this
ellipse, if drawn
through its centre,
represents one inch in the direc-
tion of that line
See also Fiqure 26
Minor axis for
Siqht anqle level
no minor axis
By comparing a
-v foreshortened length
with its ordinary (flat)
length as in Figure 15,
we determine the sight
angle, shown thus: >
and using this we ob-
tain the minor axis for
Lenqth of arcs are
foreshortened lenqths a known major axis.
THREE DIMENSIONAL DRAWING WITH UNEQUAL PLANES
Trimetric drawing is a branch of descriptive geometry by which
objects are viewed at different angles from those used in isometric
projection. It is of course possible to depict an object at any angle to
the eye, the extreme case being when one or even two of the co-
ordinate planes are so foreshortened that they almost fade out of the
picture, as in Figure 19.
Fiqure I 8
No purpose is served by drawing views with excessive foreshorten-
ing unless special requirements demand that particular aspect. Some of
the most useful aspects are those in which one plane of the figure is
parallel to one of the isometric^planes. This also permits the use of
isometric ellipse masks and scales, should you possess them.
It has been shown that objects resting at an angle on the isometric
plane are not difficult to draw, and in this manner, we are introduced
to Trimetric aspects.
Figure 17 on page 19 shows a ring of cylinders set out on the top
isometric plane, (it could be on either of the other planes); each
cylinder has a cube at its outer end. Each and every cube on the
perimeter retains the isometric scale for the vertical lines as it is
resting on an isometric plane.
In this view the cube is shown thirty-six times, i.e. spaced 10
isometric degrees apart, and for the purpose of analysis, this number
may be divided by four because each aspect is repeated four times, as
it is in the orthographic plan view.
Examination will show that cubes 90 isometric degrees apart have
the same aspect exactly as have the orthographic squares in Figure 16.
We therefore have a choice of eight different aspects which are
trimetric in addition to the isometric cubes, which are of course
repeated four times.
Aspect B is ideal for trimetric views because it strikes a good
balance without too much foreshortening or being too near to the
Trimetric is of course more
difficult to draw than isometric be-
cause it requires three different
scales, and uses ellipses of three
different major/minor proportions,
but it gives a wider scope for expres-
sion by providing a choice of six
viewing aspects using the same scales
and ellipses. The method of setting
out a trimetric cube is shown on page
23. Such a cube provides you with
Aspect B the angles and foreshortened scales.
Six aspects of a I -inch cube using the same three scales and the same
In addition six upward views can be made.
Figure 2 3
SettUuf out a ^^Umet/Uc Cube
To draw a Trimetric cube with its top
plane at the Isometric angle of sight: Draw
a plan of the top plane rotated to the atti-
tude required. Surround it with an em-
bracing square, drawn with a 45° set square,
as shown by fine lines in Figure 24. Project
the corners of the embracing square down-
wards and set out its isometric translation.
This diamond shaped form is drawn with a
30° set square, and is therefore a normal
top isometric plane. The corners of the
inner square projected down to the dia-
mond will give the four points from which
the trimetric top plane can be drawn. The
vertical edges of the trimetric cube are
drawn to isometric scale
so that the trimetric
cube may be completed.
Another method is shown in Figure 25 above.
It is a good plan to draw a six-inch cube using this
By dividing one of each of the edge lines into
six equal parts you have the three scales needed
for this aspect.
NOTE THAT THE
SPINDLE <fcs ARE
EACH PARALLEL TO
EDGE LINES OF THE
CUBE AND THAT
MAJOR AXES OF ALL
ELLIPSES ARE AT
A 2-in. cube with three ^-in. diameter spindles
projecting 2 in. from faces (aspect B). Each spindle
has eight ^-in. diameter cylinders I in. long radiat-
ing from it. These are spaced 45° apart. The scale
length of the cylinders on each plane can be obtained
c v „rr, n \ a ■ Tk.c i a „ n fk from the spindle ellipse
example . I his length ~ ~
- D x 2 /-">v on its own plane.
Fiqure 2 6
Drawn at Trimetric
Example : This lenqth - B x 2
Idi&lfuJL fyacti about tke ZlUpAje
SHORT CUTS TO ACCURACY
Three methods of correlation of ellipse proportion and scale of axial
centre line, Figures 27, 28, 29 and 30. This is applicable to ellipses of
Figure 2 7 ^~^\ \ Figure 28
for 2 inch maj
2 inch dia. cylinder
2 inches long.
of axial (£
The two dots •
are also the foci
of the ellipse.
Figure 29 It should be noted that the measurements
obtained when using the method shown in Figure 28
are inversive i.e. by feeding in one known factor, be it axial scale, sight
angle or minor axis, two factors are obtained.
The isometric ellipse. /8 major.
is used for proportioning all the
slots as shown.
Six slots 4 wide
Drawn at 25 angle
Any circle on the flat view which can be used
for projection to other locations on its own
plane can also be put to the same use when translated to its elliptical
form on its tilted plane.
Fiaure 3 2
The five rings are all l^-in. outside diameter, I in. inside diameter,
and £ in. thick. Although they have been tilted haphazardly, it was a
simple matter to determine their foreshortened thickness.
External and internal radii are difficult to indicate because their
merging zones are nebulous. It may, however, be considered draughts-
man's licence to indicate them in the manner shown below, the sole
criterion being usefulness in suggesting what is otherwise difficult to
portray without resorting to shading.
Fillets on castings are best depicted as shown. The intensity of
such lines must be left to the imagination of individual draughtsmen,
but generally it is better to make them fade out rather than to end
The drawing of helical springs on any three-dimensional drawing
appears at first glance to be a formidable task but if tackled in the right
way does not present great difficulty.
As the shape of a helical spring is repetitive along its length,
great economy of drawing time can be brought about by the use of a
stencil mask. This can be made from good quality thin cardboard or
from thin transparent plastic sheet.
Only one turn of the spring need be cut in the stencil mask (see
Figure 37) as it can be moved along the edge of the set-square in such
a manner as to produce the outline of a spring with as many turns or
coils as are required.
The first necessity is to draw the centre-line of the wire as it
winds around the axis of the spring.
Let us take for example a compression spring with the following
dimensions: pitch diameter 1^ in. — pitch of helix | in. — Wire diameter
Set out the pitch diameter (which is of course in full scale) about
the axis of the spring. If it is to be drawn in isometric set out its helical
pitch in isometric scale as shown below, and divide it into four equal
parts which will give five lines identified
as shown. On each of these five lines
draw an isometric ellipse — l^-in. major.
Consider that the major and minor axes are identified as shown
opposite, Figure 34 right.
The next stage is to mark a point on each of the five ellipses
starting at the top A and progressing downwards one line at a time,
the points being a quarter of the helical pitch and a quarter of a turn of
the diameter apart. Thus l-A, 2-B, 3-C, 4-D, and finally 5-A.
Two points l-A and 5-A are therefore one helical pitch apart,
and the five dots are points on the helix which is yet to be drawn.
With practice it is possible to slide the elliptical mask downwards
at a steady speed and at the same time move a pencil point around the
ellipse so as to synchronize each quarter of a turn with one quarter
Figure 1 3 6
pitch movement, thus drawing a continuous
helical curve for one complete coil. This merely
represents the 'back-bone' of the spring wire, so
it is necessary to put the 'meat on the bone' by a
number of circles measuring the full scale dia-
meter of the spring wire, see Figure 36.
Think of them as spherical beads. A curve
touching their diameters gives a true silhouette outline of the spring
Thin wire springs may be represented by a single thick helical line
drawn with the aid of a simple mask or directly on to the drawing using
the slowly sliding ellipse mask. See page 37 for an example.
SQUARE SECTION SPRINGS
The outline curves of these springs (both inside and outside) are
helices of the same pitch, but naturally of different diameters. These
are most conveniently drawn with a mask as shown in Figure 38, using
two separate openings so that by super-
imposing the two curves upon each other the
final outline is obtained as in Figure 39.
Fiqure 3 8
The square section spring is viewed at a 20° angle therefore a 20 c
ellipse mask was used for setting out the helices.
Hexagon nuts are best depicted at the
aspect shown i.e. with three flats showing.
Here again, the ellipse (at its correct
tilt) is of great use for determining the
angles of the sloping side faces.
In the bottom view the method of
deciding the base angles is shown with
general construction lines.
The thickness of the nut is of course
measured in the appropriate scale for the
A Actual thickness of nut
*fke Pwjeatixm o^ in/ieKjddci/i £Uxzp&i
Trimerric aspect B
Objects of irregular shape may be drawn with a crate of structure
lines as shown above, Figure 41.
The shape to be translated (the flat view) is covered by a grid of
lines equally spaced in both directions. This grid is then drawn at the
aspect required using the appropriate scales for height, width and
thickness used for that aspect.
To avoid confusion, number the grid lines in both directions. It
is a simple matter to transpose points from the flat grid to the pictorial
grid and complete the picture with the aid of French curves.
Too few draughtsmen and designers possess the ability to produce
quick freehand technical sketches, yet it offers a good many advantages
and presents wide scope for quick and clear expression.
A designer frequently wishes he could have before him a sectioned,
part-sectioned or even transparent model when demonstrating, dis-
cussing or planning some modification or improvement to an existing
piece of mechanism. The ability to sketch with confidence and accuracy
grows with practice so that this wish can be gratified.
Parts can be cut away or ghosted in by the practised hand with a
facility that almost makes a pencil into a magic wand.
It will be found that the 30 and 60 degree angles can be estimated
with fair accuracy and that after a little practice it will be possible to
draw good ellipses with a single freehand sweep of the pencil.
Many sketchers are discouraged because they have never learnt,
or have failed to grasp, the basic rules of three-dimensional drawing,
particularly the angles at which the ellipses are drawn on the planes
facing left and right, yet they are confident when drawing those on the
top plane (see Figure 26, page 24).
How often one sees technical contributions entirely spoiled by
the accompanying illustrations. Much of the puzzlement with regard
to correct orientation of ellipses can be avoided if the draughtsman
has before him a cube drawn at the aspect being used with an ellipse
on each visible face of the cube.
By sketching it is possible to work out a complete design down
to the last detail so that, from then on, the orthographic general
arrangement can be set down with great overall saving of time.
As the student progresses through the pages of this book he may
become aware of a certain amount of repetition and of the fact that
many of the problems can be solved in more than one way. This is done
to foster a fuller understanding of the subject as a whole.
The very fact that alternative methods are possible shows that the
answers are exact geometrical solutions of a given problem and not
In practice the draughtsman will naturally use the method most
suited to the particular task in hand.
On page 40 a specially devised object is shown in orthographic views
followed by its three-dimensional translations. It is not a drawing of
any particular component but has been designed solely for use as an
Effort has been made to embody difficult features which might
daunt the draughtsman as yet unversed in pictorial drawing.
Three-dimensional translations of this exercise-piece will be built
up stage by stage, with page numbers given so that the reader may
refer to the geometry embodied in that particular stage.
Figure 4 2
The drawing of complicated shapes
from a dimensional point of view,
such as a complete car, is not norm-
Ta+lx dealt with in isometric drawing.
k* There are times, however, when
,<a^e*iigqer V»shes to visualize a sub-
ject the^ifrmensions of which are
^attfef in/definite because of its many
U§ing- isometric as a basis, it is
n©t difficult to build up the guide
lines by the *so far along — so far up —
so far in* method. Even if the product
is not a work of art, the designer
has at least got something down on
paper for his own critical analysis, and so produces a basis for con-
tinued study and experiment.
Ofcwieisue View, o^ (look&i Qea/i
EXPLODED VIEW OF
QdkoKyuzpUic. View* o/ Ga^ilWf
L ii a
Valve box castinq
with cored passages.
Figure 4 5
Section A A
OiXMM&blic View- Qjj QoiilHXj,
Fiqure 4 6
When designing a casting which has intricate passages, a designer
derives much benefit by using isometric, freehand or otherwise.
By reversing conditions, showing cored passages as positive
shapes, he helps the patternmaker to plan the moulding method with
a great saving of time.
Fiqure 4 7
(Positive) Isometric view of cored passages
OF EXERCISE PIECE
Figure 4 8
Dimensions have been omitted
Draw Datum centre lines
which should be marked
to ensure clear identifica-
tion. Convert lengths
taken from orthographic
views, see Figure 51 be-
low, to isometric lengths
and set them out on the
Datum lines. Draw in iso-
metric base shape, using
light pencil lines.
Draw thickness of flange
above base, isometric
See also Figures 8 and 9
The main body shape is
now drawn in. The important
positions marked thus: are
found by measurements up-
ward from the base plane and
across, parallel with the base
lines on the orthographic view,
and converted to isometric
It is essential that the new
measurements are only used
vertically or on the lines drawn
with the 30° set square.
Having set out the frontal
shape, the back can be pro-
jected as shown. The angular
lines which form the axes of
the circular portions are also
determined by measurements
converted in the usual way.
Choose definite points on
the orthographic view and re-
peat them after scale conver-
sion on the isometric view.
In this case the topmost
point on the axial (£ of each
cylinder and the point where
the cylinder axes converge on
the vertical (£ are marked • .
Measure orthographic view
vertically and horizontally.
Convert to isometric scale.
Set out in isometric directions.
Minor for I major
Minor for Vi
length of cyl.
In the previous stage we have established the foreshortened
lengths of the cylinders A and B, and with this knowledge we can now
complete what would normally be the most difficult part of the
Figure 54 shows the method used for converting each of the two
foreshortened lengths into its own particular sight angle and the geo-
metry employed to find the ellipse proportion used for each axial <£.
It also gives us the position of each ellipse along its axial (£.
Reference may be made to Figure I I, page 14; Figure 15, page 17 and
Figure 29, page 25 as these have a bearing on the particular problems
embodied in this exercise.
ISOMETRIC AND TRIMETRIC DRAWING
The value of isometric drawing as a means of illustrating such things as instructional
handbooks has long been recognized, and greater use is now being made of it in workshop
drawings, either to supplement, or occasionally as a substitute for, the more conventional
orthographic views. However, as the author shows in this book, the usefulness of isometric
and trimetric drawing does not end here. It can be a most valuable tool for the designer
Many otherwise experienced draughtsmen have in the past been deterred from trying
their hands at this form of drawing by a mistaken belief that there is something mysterious
or complicated about it; a belief which has been perpetuated by the lack of any simple and
practical work dealing with the subject. The present -book sets out to remedy this deficiency,
and shows that isometric and trimetric drawing are geometrically pure forms of drawing,
well within the scope of the average draughtsman, using only standard drawing office
The treatment is essentially practical; theory and basic principles are introduced as
needed, and being linked to the immediate problem of producing a drawing, are quickly
and easily grasped, even by the novice. After explaining the basis of isometric projection,
the author goes on to discuss the isometric scale and its construction. The important
subject of drawing ellipses rapidly and accurately is next dealt with, and the knowledge
already gained is then applied to the drawing of angular subjects and attitudes. This leads
naturally to the consideration of the isometric aspects, through which the student is
introduced to trimetric projection. More advanced work with the ellipse follows, and the
problems of drawing some specific subjects are then considered — helical springs, hexagon
nuts, and irregular shapes are all dealt with in detail. Freehand drawing and sketching form
the subjects of the next sections, and here it is shown how three-dimensional drawing can
aid the designer in his work. Finally, following some examples of actual isometric drawings,
a carefully designed exercise piece is presented, and the problems of drawing it are
discussed in detail.
The work is copiously illustrated, preference being given at all times to clear drawings
rather than wordy explanations of the points under discussion. A large page size has been
chosen, so that the illustrations can be reproduced in full scale. Many valuable hints and
tips, the fruit of the author's own experience, are given, and this information, most of
which has never previously been published, makes the book of value alike to the experienced
draughtsman and to the student.
PRICE |0/- NET
A HEYWOOD BOOK
Published by Temple Press Books Ltd
42 RUSSELL SQUARE, LONDON WCI